For a long time the way to get free United Club access has been to match status to Turkish Airlines Miles&Smiles. They’ve been inconsistent over the years in how they’ve accepted matches (first via email and then via web form), how long they’ve taken to reply (quickly vs months), and what status they’ve been willing to match (sometimes United status, sometimes only competitor alliances, sometimes only top tier status). But it’s status that lasts two years.
It turns out there’s another Star Alliance program offering status matches, and there are successful reports from United and American elites both of getting matches that allow for United Club access.